Telephone interviewing has become an increasingly attractive option in survey research, and is both a faster and less costly mode of data collection than face-to-face interviewing. Although widely used in marketing, political, and attitudinal research, little is known about the efficacy of telephone interviewing for highly sensitive surveys on drug abuse, such as the periodic National (Household) Survey on Drug Abuse (NHSDA) conducted by NIDA. Will telephone respondents answer questions on the illicit use marijuana and cocaine, or on embarrassing topics such as treatment for drug problems and alcoholism? How will a switch from personal to telephone methods affect the data's reliability and validity? Can Random Digit Dialine (RRD) produce a sample of respondents comparable to the area probability sampling used in in-person surveys? These questions must be addressed before a change in methodology for the NHSDA can be made. To this end, ISR proposes to conduct a feasibility study of telephone interviewing in drug use surveys. An RDD sample of the adult household population (age 18 and over) of the State of New Jersey will be drawn, and 2,000 telephone interviews will be completed using a subset of core drug use items from the current NHSDA questionnaire. Results of the proposed telephone survey will be compared to the personal interview New Jersey Drug Study to be conducted by ISR in Spring, 1986. In this survey, which also uses the current NHSDA questionnaire, ISR will complete 1,000 interviews with a household area probability sample of the state. To evaluate the feasibility of telephone methodology, the two surveys will be compared on the following items: demographic characteristics of the sample, nonresponse bias, item nonresponse and other psychometric properties of the questionnaire, response set bias, interviewer effects, respondent reactions to the interview, quality control, prevalence estimates, and costs per interview. In addition to the full survey, an RDD sample of 150 adults will be asked to act as judges in study of social desirability response set bias in the NHSDA. Techniques developed by Edwards (1970) and Paulhaus (1981); 1984) will be used to estimate the influence of social desirability on self reports of drug use in both the personal and telephone surveys.